More than 800,000 patients worldwide suffer from chronic renal failure. Renal failure is most often the result of inflammatory diseases of the kidney, leading to a continuous decline of the kidney function until the kidneys are no longer able to keep the levels of certain toxic substances in the blood at low levels. Also those suffering from diabetes and chronic abusers of pain relief drugs may experience chronic renal failure.
Hemodialysis is a widely used treatment modality for individuals whose kidneys are unable to remove undesirable products from their system, due to acute or chronic reasons. When the damage is irreversible and the kidneys cannot recover their proper functions, the person is in a state of end stage renal disease (ESRD).
To maintain one's state of health there are three treatment modalities available, those being:1. renal transplant, 2. peritoneal dialysis, and 3. chronic hemodialysis. Even though the first two modalities are often used, chronic hemodialysis is by far the most widely used treatment.
In order to provide this treatment, a vascular access is used as part of a system of allowing the blood to be circulated extracorporaly in a dialysis machine and then to re-enter the body. The most widely used methods of vascular access are:1. a direct arteriovenous anastomosis (Cimino type), 2. a large bore external venous catheter, or 3. a tube planted subcutaneously and anastomosing one end to an artery and one end to a vein (arteriovenous (AV) graft).
For a variety of reasons, the AV graft is the most widely used at the present time. Typically the graft is planted subcutaneously in an extremity with one end anastomosed to the artery and the other end anastomosed to the vein. This allows the blood to circulate at a high velocity in the graft.
When the graft is matured (ready to be used) it is accessed by inserting a large bore needle in the arterial side. The blood then comes out from the arterial needle and enters via an external tubing system into the dialysis machine. After the blood is dialyzed, it re-enters the graft via the venous side.
This method is very effective but because of the need to repeatedly cannulate the graft by introducing a sharp needle, there is a high rate of complications. These complications and problems include a great deal of discomfort for the patient, loss of function of the graft and a financial drain. These complications, most of which are caused by repeated cannulation of the graft, include infection, thrombosis, false aneurysm, bleeding, skin necrosis, skin sloughing and also pain and discomfort to the patient each time they have dialysis.